Coconut water is the trendy health drink of the day. Its advocates speak of health benefits like vitamin B and potassium, and it’s supposed to be great after a workout. And in a pinch, a coconut can even be used as an all-natural IV bag.

According to i09, coconuts were rumored to have been used as IV drips during World War II and the Vietnam War, and it turns out that it actually works. There is a documented case of a coconut being used as an IV in a small hospital in the Solomon Islands, where a man was brought in with partial paralysis and a fever. The patient became dehydrated because he could not consume fluids, but the hospital was running low on IV bags. Instead, someone picked a coconut, which they punctured with a needle and then attached to the patient’s arm with an IV tube. After two days, the patient recovered and went home.

"Coconuts, although not ideal, are well-suited to use as rehydration IVs," writes i09’s Esther Inglis-Arkell. "As long as they aren't cracked open they are sterile, the water inside them is a little like the intracellular fluid that we have in our bodies, and they have the same overall specific gravity — density when compared to water — as human plasma."

Neat, isn’t it? Science is awesome. Coconuts are pretty cool, too. If you don’t feel like jabbing one into your arm, check out some of our best coconut recipes for some more conventional preparations.